1. Field of the Invention
The present invention relates to a machine for the production of a tissue web, with a nip formed between a drying cylinder, in particular a Yankee cylinder, and a press shoe arrangement that can be pressed against the drying cylinder via several contact pressing elements arranged in at least one row extending crosswise to the web travel direction.
2. Discussion of Background Information
Up to now, press shoes were pressed uniformly across the width or with a lower pressure at the edges.
However, the contour of a Yankee drying cylinder of a tissue machine now changes as a result of the steam pressure internally as well as due to a temperature expansion of the face cover. If a press shoe is then pressed against the Yankee cylinder to form a press nip, the course of the pressing pressure in the crosswise direction is no longer constant, but deviates upwards or downwards at the edges. The deviations are not always constant, but depend on the operational parameters, e.g., basis weight, speed, steam pressure, temperature, linear load of the press nip and/or the like. As is known, the linear load can be calculated, as is known, from the pressing pressure profile and the nip geometry. For the same press shoe there is a well-defined correlation.